Mechanism for stretching artificial filaments



Dec. 25, 1951 D H rr- 2,579,555

MECHANISM FOR STRETCHING ARTIFICIAL FILAMENTS Filed Aug. 28, 1950 2 SHEETS-SHEET l IN V EN TORS /V/c0z.As OBI-SCH ,4 ND 196/1 5 54 K)" Dec. 25, 1951 DR|SH ETAL 2,579,555

MECHANISM FOR STRETCHING ARTIFICIAL FILAMENTS Filed Aug. 28, 1950 4 2 SHEETS-SHEET 2 IN V EN TOR) N/coL AsD/PAS CH BY AND lPf/VE FAYJ wig A T TORNEX friction of the rollers on their spindles.

Patented Dec. 25, 1951 MECHANISM FOR STRETCHIN G ARTIFICIAL FILAMENTS Nicolas Drisch and Rene Fays, Paris, France, as-

signors, by mesne assignments, to Textile and ChemicallResearch Company Limited, St. Peter, Port of Guernsey, Channel Islands, :1. corporation of Great Britain Application August 28, 1950, Serial No. 181,762 In France July 29, 1949 Claims.

This invention relates to mechanism for stretching artificial filaments.

In the spinning of artificial filaments the filaments are commonly stretched as they leave the spinneretand while they are still soft or plastic in order to increase their dry and wet strength and several arrangements for performing this operation are known.

Thus, it is known in wet spinning (for example. in the spinning of viscose in a coagulating bath) to pass the yarn spun from the filaments successively over a series of rollers loosely mounted on their spindles in the bath, the diameters of the rollers being the same or not, after which the yarn is passed to a winding or other device which draws the yarn along. A stretching tension is applied to the yarn due to the reduction in the speed of rotation of the rollers by the drag on the rollers of the liquid in the bath and/or by the The rollers may be provided with means, such as blades, positively to decrease their speed of rotation, as disclosed for example, in U. S. Patents Nos. 2,083,251 and 2,083,252 dated June 8, .1937.

It is also known to pass the yarn successively into grooves formed in rollers of progressively increasing diameter, the rollers being arranged in banks as, for example, in the arrangement disclosed in German Patent Specification No. 625,352 of March 18, 1932.

Another stretching machine comprises one or more fixed elements (for example rods) placed outside the bath, the yarn being passed over the elements so that the friction between the yarn and the elements results in the yarn being stretched. Such an arrangement is described, for example, in German Patent Specification No. 517,324 of the 18th of March, 1926, and in German Patent !No. 544,001 of March 25, 1927.

It is also possible in a device in which the yarn follows a sinuous path between the tips of two sets of pivoted rods, the rods of each set being parallel and either or both sets of rods being adjustable, to vary the extent of the zig-zag of the yarn in passing between the sets of rods. Such an arrangement is disclosed in U. S. Patent No. 2,030,189 dated February 11, 1936.

It is also known (see French Patent Specification No. 738,054 of June 2, 1932) to make the yarns follow a zig-zag path between a number of pins suitably carried in the coagulating bath, the stretching eifect being progressively increased in the direction of travel of the yarn by arranging either that the pins come progressively closer together from the feed to the delivery ends of the stretching mechanism or that the extent of the zig-zag increases towards the delivery end by progressively spacing the pins apart to a greater extent in a direction transverse to the general direction of movement of the yarn.

The object of the present invention is to provide an improved mechanism in which the stretching of the artificial yarn is first performed in a device comprising two grids of parallel bars, one grid being mounted for pivotal movement about an axis parallel to the bars, the arrangement being that the yarn follows a more sinuous path as the two grids are brought together, for example, under the action of a counter-weighted lever and is secondly performed with passage over two or more rollers of successively greater diameters. One or more guide rollers may precede the grid device.

The present invention may be generally applied to the stretching of artificial yarns immediately following spinning, but has particular advantages in the spinning of viscose in coagulating baths of concentrated sulphuric acid as set forth in the specifications accompanying U. S. applications Serial Nos. 30,153 and 30,154 filed May 29, 1948 (now abandoned and replaced by application Serial No. 30,155 filed May 29, 194 8) since it is then possible to impose a stretch of from 300% to 400% and in favorable conditions even more.

The invention also comprises certain detailed improvements which will be more fully described with reference to the embodiment of the invention illustrated in the accompanying diagrammatic drawing which is given by way of example only.

In the drawing, the spinneret I is mounted on its support 2 and is immersed in the usual manner in the coagulating hath (not shown). The yarn 3 which comprises a plurality of filaments having a fineness of 0.1 denier or less, is coagulated in the bath, and if the latter has, for example, a concentrated sulphuric acid base, as set forth in the specification of British Patent application No. 12944/48, the thread is very highly plastic. The filaments 3 converge over a distance of, for example, 40 cm. towards a concentrating roller 4 mounted loosely on the spindle 5, outside the bath. The bath solution may splash on to spindle 5 and act as a lubricant for roller 4.

The yarn formed by the filaments leaving the roller 4 then travels towards a roller 8 which is loose on a spindle l and has a diameter 0130 mm., for example. From there, the yarn passes through a grid device 8 constituting one of the essential elements of the invention. The grid device comprises two sets of rods each of which, in the particular arrangement being described, comprises three rods but this number obviously varies according to requirements, that is, it may be increased for a greater drafting effect in the grid or reduced to diminish the effect. The rods are parallel and made of inert material, for example of glass, stainless steel or sintered alumina. The grids are arranged one above the other, the top grid comprising the rods a, b, c, and the bottom grid comprising the rods (1', b, c. The rods a, b, c, are all secured at their ends a to a bar 9, while the rods a, b, c, are secured to a bar 9' lying below bar 9. The lower bar is fixed (i. e. immovable) and bar 9 is arranged to pivot about hinge Ill. The free end of bar 9 carries a rod Ii along iustable to vary the downward pressure on the upper grid comprising rods a, b, c.

The yarn is laid between the grids after liftthevbar 9 so that the yarn passes over the rods b, c' and under the rods a, b, c.

The top grid is then lowered and applied to the yarn by weight 12 so that the yarn follows a sinuous or slightly zig-zag path, the amplitude of the zig-zag increasing from the feeding end to the delivery end. Under the pressure of the upper grid the yarn tends to arrange itself in the form of a flat band or ribbon, which is an advantage as will shortly appear.

In the grid device described, a stretch of from 100% to 150% can be produced dependent on the weight 12, the position thereof along its fulcrum arm and the tension of the yarn. The latter is inter she. a function of the diameter of a roller I3 which is mounted on a vertical spindle [4 (the roller having a diameter of, forrexample, 45 mm.) and of the diameter of the roller 6 (which is, for example, about 20 mm.)

The spreading out of the bundle of filaments into a ribbon by the grids improves its adhesion to the roller l3. From roller l3 the yarn passes, still in ribbon form, to a large, grooved roller l that is mounted on spindle 1. This roller may have a diameter of, for example, 100 mm. at the bottom of the groove.

In passing over the rollers the yarn is further stretched by some 120% and on delivery from roller l5 the yarn may pass to a feed roller not shown to undergo a further stretch before performing the finishing processes, e. g. washing, drying, and winding. Alternatively the yarn may follow a lengthy path between roller l5 and the winding device during which it is stabllized'as described in U. S. Patent application Serial No. 9,115, filed February 18, 1948.

The rollers 8" and 15 are formed with radial passages l6 and I1 extending from the peripheries of the rollers to the spindle 1 so that the coagulating solution passes to the spindle I as a lubricant therefor. The roller l3 and/or the spindle i4 is or are grooved helically to draw up bath solution between the spindle and roller for the purposes of lubrication.

According to the drawing, the yarn is lapped part way around the rollers 6, i3 and i5, but it which a weight i2 is ad-' may obviously be wound over a larger arc; or wrapped several times around the rollers in known manner with the aid of suitable guides.

What is claimed is:

1. In a mechanism for stretching a bundle of acid-wet artificial regenerated cellulose filaments received from a spinneret, a grid comprising a pair of sets of spaced parallel interleaved rods, a fixed member carrying one of said sets of rods and a pivoted member carrying the other of said sets of rods with the rods of the two sets displaced to provide a zig-zag path of increasing sinuosity for the filaments passing thereover, said last member being pivoted for movement about an axis parallel to said rods whereby the overlap of said path may be varied, and means urging said pivoted set of rods into position of increased overlap with respect to the fixed set of rods, and cooperating with said grid, apair of rollers of different diameters, the smaller of said rollers guiding the filament bundle from thespinneret to the said grid and the larger of said rollers receiving the filament bundle from saidj'srid, whereby the bundle is first stretched by friction on the said grid and is further stretched between said grid and the second of the rollers.

2. A mechanism for stretching artificial filaments, as set forth in claim 1, in which a weight is adjustably supported by said pivoted member in position to urge said rods into positionof increased overlap.

3. A mechanism for stretching a bundle of plastic acid-wet artificial filaments of viscose freshly coagulated by concentrated, sulphuric acid, comprising a pair of sets of spaced parallel rods, members carrying the respective sets positioned to yieldingly hold the rods in overlapping position to provide a zig-zag path for the filaments thereover, guide rollers guiding the file.- ments to and from said sets of rods, spindles carrying said rollers, and means supplying liquid from said filaments to said' spindles as a lubricant.

4. A stretching mechanism as set forth in claim 3 in which said lubricating means comprises radial passages in said rollers extending inwardly to said spindles.

5. A stretching mechanism as set forth in claim 3 in which said lubricating means comprises helical grooves in one of the adjacent surfaces of said spindles and rollers.

mcoms DRISCH. RENE FAYS.

, file of this patent:

UNITED STATES PATENTS Grimes, Sr. Dec. 12, 1944 

1. IN A MECHANISM FOR STRETCHING A BUNDLE OF ACID-WET ARTIFICAL REGENERATED CELLULOSE FILAMENTS RECEIVED FROM A SPINNERET, A GRID COMPRISING A PAIR OF SETS OF SPACED PARALLEL INTERLEAVED RODS, A FIXED MEMBER CARRYING ONE OF SAID SETS OF RODS AND A PIVOTED MEMBER CARRYING THE OTHER OF SAID SETS OF RODS WITH THE RODS OF THE TWO SETS DISPLACING TO PROVIDE A ZIG-ZAG PATH OF INCREASING SINUOSITY FOR THE FILAMENTS PASSING THEREOVER, SAID LAST MEMBER BEING PIVOTED FOR MOVEMENT ABOUT AN AXIS PARALLEL TO SAID RODS WHEREBY THE OVERLAP OF SAID PATH MAY BE VARIED, AND MEANS URGING SAID PIVOTED SET OF RODS INTO POSITION OF INCREASED OVERLAP WITH RESPECT TO THE FIXED SET OF RODS, AND COOPERATING WITH SAID GRID, A PAIR OF ROLLERS OF DIFFERENT DIAMETERS, THE SMALLER OF SAID ROLLERS GUIDING THE FILAMENT BUNDLE FROM THE SPINNERET TO THE SAID GRID AND THE LARGER OF SAID ROLLERS RECEIVING THE FILAMENT BUNDLE FROM SAID GRID WHEREBY THE BUNDLE IS FIRST STRETCHED BY FRICTION ON THE SAID GRID AND IS FURTHER STRETCHED BETWEEN SAID GRID AND THE SECOND OF THE ROLLERS. 